1. Field of the Invention
This invention relates to thin metal films. More specifically, the invention is a flexible thin metal film thermal sensing system.
2. Description of the Related Art
Electrically-based thermal sensing is typically accomplished using a thermocouple or resistance temperature device (RTD). A thermocouple is a passive device made out of wire or a metal film deposited on an insulative substrate. Wire thermocouples are relatively inflexible thereby making them a poor choice when the sensor must be wrapped about or otherwise conformed to the shape of a structure. Metal film-based thermocouples are typically made by thermal evaporation or sputtering of a metal film onto a dielectric surface, e.g., a plastic. If this sensor is to be mounted on a structural surface for temperature measurement thereof, the dielectric surface must be (i) doped to make it thermally conductive, and (ii) pre-shaped to fit the portion of the structural surface on which it is to be mounted.
RTDs are active devices in that an electric current must be supplied thereto with a resulting electrical resistance being read therefrom. The electrical resistance is indicative of temperature. RTDs are typically made from metal foils that are thicker and less flexible than a metal film thermocouple. Accordingly, RTDs may not be suitable choices for temperature sensing applications requiring relatively small and flexible temperature sensors.